Ok..
I get that Jeremy states that he went to get hold of a brand new box of 50 X .22 ammunition from the gun cupboard in the Den for the purpose of loading the magazine of the anschutz rifle so that he could go and try to shoot rabbits that he had seen in the barn area minutes beforehand...
But..
The maths are all wrong, involving the number of the 50 rounds of ammunition used up in the shootings, (20), and the number of spent cartridge cases / bullets that had been loaded twice into the magazine of the gun, which according to Jeremy, included one such a double magazine marked bullet which he said he had removed from the rifles breech, prior to him leaving the rifle on the settle! If Jeremy had done what he claims he had done with that bullet, and he had placed it back into the ammunition magazine, as stated by him, then that round would have been one of the five bullets which were found to have got double magazine markings upon it!